This invention relates to toilet flush valve systems of the type through which two different flush volumes of water may be released in order to evacuate a toilet bowl.
Toilet bowl flush systems of the foregoing type enabling the user to select two different quantities of flushing water, have already been devised in connection with water conservation programs. However, such prior dual volume flushing systems usually create certain drawbacks insofar as operational reliability and manufacturing costs are concerned.
According to one known type of dual volume flushing system, the usual flush control lever associated with the flush tank is displaceable in opposite directions from a center position in order to select the volume of flush water to be utilized. Aside from the operational uncertainty created by such a control arrangement, a substantial linkage complexity is introduced as well as an increase in manufacturing costs. Examples of such dual volume flushing systems are disclosed, for example, in U.S. Pat. Nos. 4,096,591 and 4,172,299.
Another type of dual volume flushing system wherein the flush control lever is displaced in one direction only for a sequential two-stage flush operation, is disclosed in U.S. Pat. No. 3,768,103. According to the latter patent, two pivoted flap valves are located on one side of a vertical outlet tube directly below each other. A single actuating chain interconnects both flap valves with the flush lever. The control arrangement in such case makes operation difficult and unreliable.
It is therefore an important object of the present invention to provide a flush valve assembly of reduced cost for a dual volume flushing system of the latter mentioned type which provides for a smoother and more reliable flush operation utilizing either a smaller or larger flushing volume of water in a more facile manner.